Experimental sheep BSE prions generate the vCJD phenotype when serially passaged in transgenic mice expressing human prion protein
Experimental sheep BSE prions generate the vCJD phenotype when serially passaged in transgenic mice expressing human prion protein
Susan Joinera , Emmanuel A. Asantea , Jacqueline M. Linehana , Lara Brocka , Sebastian Brandnera , Susan J. Bellworthyb , Marion M. Simmonsb , James Hopeb , John Collingea , Jonathan D.F. Wadswortha,⁎ a MRC Prion Unit at UCL, UCL Institute of Prion Diseases, London, UK bAnimal and Plant Health Agency, Addlestone, Surrey, UK
ARTICLE INFO
Keywords: Bovine spongiform encephalopathy (BSE) Prions Prion disease Variant Creutzfeldt-Jakob disease (vCJD) Sheep-BSE Transmissible spongiform encephalopathy (TSE)
ABSTRACT
The epizootic prion disease of cattle, bovine spongiform encephalopathy (BSE), causes variant Creutzfeldt-Jakob disease (vCJD) in humans following dietary exposure. While it is assumed that all cases of vCJD attributed to a dietary aetiology are related to cattle BSE, sheep and goats are susceptible to experimental oral challenge with cattle BSE prions and farmed animals in the UK were undoubtedly exposed to BSE-contaminated meat and bone meal during the late 1980s and early 1990s. Although no natural field cases of sheep BSE have been identified, it cannot be excluded that some BSE-infected sheep might have entered the European human food chain. Evaluation of the zoonotic potential of sheep BSE prions has been addressed by examining the transmission properties of experimental brain isolates in transgenic mice that express human prion protein, however to-date there have been relatively few studies. Here we report that serial passage of experimental sheep BSE prions in transgenic mice expressing human prion protein with methionine at residue 129 produces the vCJD phenotype that mirrors that seen when the same mice are challenged with vCJD prions from patient brain. These findings are congruent with those reported previously by another laboratory, and thereby strongly reinforce the view that sheep BSE prions could have acted as a causal agent of vCJD within Europe.
snip...
Due to the inherent limitations of public health and epidemiological studies to address key uncertainties related to the nature and extent of BSE-related human prion disease in the UK, surrogate methods have been developed to evaluate the relative pathogenicity of animal prions for humans [10]. One major approach involves the experimental transmission of disease by inoculation of homogenised brain tissue from affected animals into transgenic mice overexpressing one or other of the two common polymorphic forms of the human prion protein (PrP) with either methionine (M) or valine (V) at residue 129 on a mouse PrP null background. Experimental transmission of BSE and vCJD prions to such mice has demonstrated the critical role of residue 129 polymorphism in determining susceptibility, incubation time and pathological phenotype (for review see Ref. [11]). These effects relate not only to the importance of homologous protein interactions in prion propagation [5,12–14] but also to the preferential propagation of different prion strains by PrP with different primary structures via conformational selection [5,11,13,14].
***Findings from these models indicate that primary and secondary human infection with BSE prions may result in sporadic CJD-like or novel phenotypes in addition to vCJD, depending on the PrP genotype of the prion source and the recipient [4,11,15].
snip...
4. Conclusions
Based upon the collective neuropathological and molecular phenotypes observed in the secondary transmission series reported here, we conclude that primary transmission of sheep BSE prions to 129MM Tg35c mice led to the propagation of the vCJD prion strain. These data concur with those of Torres and colleagues and strongly support their proposal that small ruminant BSE prions might act as a causal agent of vCJD [27]. This knowledge may have a future bearing upon understanding the zoonotic origin and epidemiology of vCJD and emphasizes the importance of continued discriminatory TSE surveillance of small ruminants within Europe [10,25].
The EMBO Journal Vol. 21 No. 23 pp. 6358±6366, 2002
BSE prions propagate as either variant CJD-like or sporadic CJD-like prion strains in transgenic mice expressing human prion protein
Volume 2: Science
4. The link between BSE and vCJD
Summary
4.29 The evidence discussed above that vCJD is caused by BSE seems overwhelming. Uncertainties exist about the cause of CJD in farmers, their wives and in several abattoir workers. It seems that farmers at least might be at higher risk than others in the general population. 1 Increased ascertainment (ie, increased identification of cases as a result of greater awareness of the condition) seems unlikely, as other groups exposed to risk, such as butchers and veterinarians, do not appear to have been affected. The CJD in farmers seems to be similar to other sporadic CJD in age of onset, in respect to glycosylation patterns, and in strain-typing in experimental mice. Some farmers are heterozygous for the methionine/valine variant at codon 129, and their lymphoreticular system (LRS) does not contain the high levels of PrPSc found in vCJD.
***It remains a remote possibility that when older people contract CJD from BSE the resulting phenotype is like sporadic CJD and is distinct from the vCJD phenotype in younger people.
BSE Inquiry
SATURDAY, DECEMBER 02, 2017
Public health risks from subclinical variant CJD
MONDAY, NOVEMBER 06, 2017
Experimental transfusion of variant CJD-infected blood reveals previously uncharacterised prion disorder in mice and macaque
WEDNESDAY, NOVEMBER 22, 2017
NIH scientists and collaborators find infectious prion protein in skin of CJD patients
WEDNESDAY, NOVEMBER 22, 2017
Prion seeding activity and infectivity in skin samples from patients with sporadic Creutzfeldt-Jakob disease
FRIDAY, AUGUST 11, 2017
Infectivity in bone marrow from sporadic CJD patients
Bioassays in transgenic mice expressing the human prion protein revealed the presence of unexpectedly high levels of infectivity in the bone marrow from seven out of eight sCJD cases. These findings may explain the presence of blood-borne infectivity in sCJD patients. They also suggest that the distribution of prion infectivity in peripheral tissues in sCJD patients could be wider than currently believed, with potential implications for the iatrogenic transmission risk of this disease.
ZOONOSIS OF TSE PRION DISEASE
O.05: Transmission of prions to primates after extended silent incubation periods: Implications for BSE and scrapie risk assessment in human populations
Emmanuel Comoy, Jacqueline Mikol, Valerie Durand, Sophie Luccantoni, Evelyne Correia, Nathalie Lescoutra, Capucine Dehen, and Jean-Philippe Deslys Atomic Energy Commission; Fontenay-aux-Roses, France
Prion diseases (PD) are the unique neurodegenerative proteinopathies reputed to be transmissible under field conditions since decades. The transmission of Bovine Spongiform Encephalopathy (BSE) to humans evidenced that an animal PD might be zoonotic under appropriate conditions. Contrarily, in the absence of obvious (epidemiological or experimental) elements supporting a transmission or genetic predispositions, PD, like the other proteinopathies, are reputed to occur spontaneously (atpical animal prion strains, sporadic CJD summing 80% of human prion cases). Non-human primate models provided the first evidences supporting the transmissibiity of human prion strains and the zoonotic potential of BSE. Among them, cynomolgus macaques brought major information for BSE risk assessment for human health (Chen, 2014), according to their phylogenetic proximity to humans and extended lifetime. We used this model to assess the zoonotic potential of other animal PD from bovine, ovine and cervid origins even after very long silent incubation periods.
*** We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period,
***with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold long incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014),
***is the third potentially zoonotic PD (with BSE and L-type BSE),
***thus questioning the origin of human sporadic cases.
We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
===============
***thus questioning the origin of human sporadic cases***
===============
***our findings suggest that possible transmission risk of H-type BSE to sheep and human. Bioassay will be required to determine whether the PMCA products are infectious to these animals.
==============
Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
PRION 2016 TOKYO
Saturday, April 23, 2016
SCRAPIE WS-01: Prion diseases in animals and zoonotic potential 2016
Prion. 10:S15-S21. 2016 ISSN: 1933-6896 printl 1933-690X online
Taylor & Francis
Prion 2016 Animal Prion Disease Workshop Abstracts
WS-01: Prion diseases in animals and zoonotic potential
Juan Maria Torres a, Olivier Andreoletti b, J uan-Carlos Espinosa a. Vincent Beringue c. Patricia Aguilar a,
Natalia Fernandez-Borges a. and Alba Marin-Moreno a
"Centro de Investigacion en Sanidad Animal ( CISA-INIA ). Valdeolmos, Madrid. Spain; b UMR INRA -ENVT 1225 Interactions Holes Agents Pathogenes. ENVT. Toulouse. France: "UR892. Virologie lmmunologie MolécuIaires, Jouy-en-Josas. France
Dietary exposure to bovine spongiform encephalopathy (BSE) contaminated bovine tissues is considered as the origin of variant Creutzfeldt Jakob (vCJD) disease in human. To date, BSE agent is the only recognized zoonotic prion. Despite the variety of Transmissible Spongiform Encephalopathy (TSE) agents that have been circulating for centuries in farmed ruminants there is no apparent epidemiological link between exposure to ruminant products and the occurrence of other form of TSE in human like sporadic Creutzfeldt Jakob Disease (sCJD). However, the zoonotic potential of the diversity of circulating TSE agents has never been systematically assessed. The major issue in experimental assessment of TSEs zoonotic potential lies in the modeling of the ‘species barrier‘, the biological phenomenon that limits TSE agents’ propagation from a species to another. In the last decade, mice genetically engineered to express normal forms of the human prion protein has proved essential in studying human prions pathogenesis and modeling the capacity of TSEs to cross the human species barrier.
To assess the zoonotic potential of prions circulating in farmed ruminants, we study their transmission ability in transgenic mice expressing human PrPC (HuPrP-Tg). Two lines of mice expressing different forms of the human PrPC (129Met or 129Val) are used to determine the role of the Met129Val dimorphism in susceptibility/resistance to the different agents.
These transmission experiments confirm the ability of BSE prions to propagate in 129M- HuPrP-Tg mice and demonstrate that Met129 homozygotes may be susceptible to BSE in sheep or goat to a greater degree than the BSE agent in cattle and that these agents can convey molecular properties and neuropathological indistinguishable from vCJD. However homozygous 129V mice are resistant to all tested BSE derived prions independently of the originating species suggesting a higher transmission barrier for 129V-PrP variant.
Transmission data also revealed that several scrapie prions propagate in HuPrP-Tg mice with efficiency comparable to that of cattle BSE. While the efficiency of transmission at primary passage was low, subsequent passages resulted in a highly virulent prion disease in both Met129 and Val129 mice. Transmission of the different scrapie isolates in these mice leads to the emergence of prion strain phenotypes that showed similar characteristics to those displayed by MM1 or VV2 sCJD prion. These results demonstrate that scrapie prions have a zoonotic potential and raise new questions about the possible link between animal and human prions.
why do we not want to do TSE transmission studies on chimpanzees $
5. A positive result from a chimpanzee challenged severly would likely create alarm in some circles even if the result could not be interpreted for man. I have a view that all these agents could be transmitted provided a large enough dose by appropriate routes was given and the animals kept long enough. Until the mechanisms of the species barrier are more clearly understood it might be best to retain that hypothesis.
snip...
R. BRADLEY
Title: Transmission of scrapie prions to primate after an extended silent incubation period)
*** In complement to the recent demonstration that humanized mice are susceptible to scrapie, we report here the first observation of direct transmission of a natural classical scrapie isolate to a macaque after a 10-year incubation period. Neuropathologic examination revealed all of the features of a prion disease: spongiform change, neuronal loss, and accumulation of PrPres throughout the CNS.
*** This observation strengthens the questioning of the harmlessness of scrapie to humans, at a time when protective measures for human and animal health are being dismantled and reduced as c-BSE is considered controlled and being eradicated.
*** Our results underscore the importance of precautionary and protective measures and the necessity for long-term experimental transmission studies to assess the zoonotic potential of other animal prion strains.
LOOKING FOR CWD IN HUMANS AS nvCJD or as an ATYPICAL CJD, LOOKING IN ALL THE WRONG PLACES $$$
*** These results would seem to suggest that CWD does indeed have zoonotic potential, at least as judged by the compatibility of CWD prions and their human PrPC target. Furthermore, extrapolation from this simple in vitro assay suggests that if zoonotic CWD occurred, it would most likely effect those of the PRNP codon 129-MM genotype and that the PrPres type would be similar to that found in the most common subtype of sCJD (MM1).***
Monday, December 1, 2008
When Atypical Scrapie cross species barriers
Authors Andreoletti O., Herva M. H., Cassard H., Espinosa J. C., Lacroux C., Simon S., Padilla D., Benestad S. L., Lantier F., Schelcher F., Grassi J., Torres, J. M., UMR INRA ENVT 1225, Ecole Nationale Veterinaire de Toulouse.France; ICISA-INlA, Madrid, Spain; CEA, IBiTec-5, DSV, CEA/Saclay, Gif sur Yvette cedex, France; National Veterinary Institute, Postboks 750 Sentrum, 0106 Oslo, Norway, INRA IASP, Centre INRA de Tours, 3738O Nouzilly, France.
Content
Atypical scrapie is a TSE occurring in small ruminants and harbouring peculiar clinical, epidemiological and biochemical properties. Currently this form of disease is identified in a large number of countries. In this study we report the transmission of an atypical scrapie isolate through different species barriers as modeled by transgenic mice (Tg) expressing different species PRP sequence.
The donor isolate was collected in 1995 in a French commercial sheep flock. inoculation into AHQ/AHQ sheep induced a disease which had all neuro-pathological and biochemical characteristics of atypical scrapie. Transmitted into Transgenic mice expressing either ovine or PrPc, the isolate retained all the described characteristics of atypical scrapie.
Surprisingly the TSE agent characteristics were dramatically different v/hen passaged into Tg bovine mice. The recovered TSE agent had biological and biochemical characteristics similar to those of atypical BSE L in the same mouse model. Moreover, whereas no other TSE agent than BSE were shown to transmit into Tg porcine mice, atypical scrapie was able to develop into this model, albeit with low attack rate on first passage.
Furthermore, after adaptation in the porcine mouse model this prion showed similar biological and biochemical characteristics than BSE adapted to this porcine mouse model. Altogether these data indicate.
(i) the unsuspected potential abilities of atypical scrapie to cross species barriers
(ii) the possible capacity of this agent to acquire new characteristics when crossing species barrier
These findings raise some interrogation on the concept of TSE strain and on the origin of the diversity of the TSE agents and could have consequences on field TSE control measures.
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were exposed to the infectious agents only by their nonforced consumption of known infectious tissues. The asymptomatic incubation period in the one monkey exposed to the virus of kuru was 36 months; that in the two monkeys exposed to the virus of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively. Careful physical examination of the buccal cavities of all of the monkeys failed to reveal signs or oral lesions. One additional monkey similarly exposed to kuru has remained asymptomatic during the 39 months that it has been under observation.
snip...
The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie by natural feeding to squirrel monkeys that we have reported provides further grounds for concern that scrapie-infected meat may occasionally give rise in humans to Creutzfeldt-Jakob disease.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
Recently the question has again been brought up as to whether scrapie is transmissible to man. This has followed reports that the disease has been transmitted to primates. One particularly lurid speculation (Gajdusek 1977) conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible encephalopathy of mink are varieties of a single "virus". The U.S. Department of Agriculture concluded that it could "no longer justify or permit scrapie-blood line and scrapie-exposed sheep and goats to be processed for human or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by the finding that some strains of scrapie produce lesions identical to the once which characterise the human dementias"
Whether true or not. the hypothesis that these agents might be transmissible to man raises two considerations. First, the safety of laboratory personnel requires prompt attention. Second, action such as the "scorched meat" policy of USDA makes the solution of the acrapie problem urgent if the sheep industry is not to suffer grievously.
snip...
76/10.12/4.6
Nature. 1972 Mar 10;236(5341):73-4.
Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis). Gibbs CJ Jr, Gajdusek DC.
Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0
Transmission of Scrapie to the Cynomolgus Monkey (Macaca fascicularis)
C. J. GIBBS jun. & D. C. GAJDUSEK
National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland
SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey (Macaca fascicularis) with an incubation period of more than 5 yr from the time of intracerebral inoculation of scrapie-infected mouse brain. The animal developed a chronic central nervous system degeneration, with ataxia, tremor and myoclonus with associated severe scrapie-like pathology of intensive astroglial hypertrophy and proliferation, neuronal vacuolation and status spongiosus of grey matter. The strain of scrapie virus used was the eighth passage in Swiss mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton, Berkshire).
Thursday, December 23, 2010
Molecular Typing of Protease-Resistant Prion Protein in Transmissible Spongiform Encephalopathies of Small Ruminants, France, 2002–2009 Volume 17, Number 1–January 2011
please see;
***Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle. In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641.
please see;
***Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle. In the US, scrapie is reported primarily in sheep homozygous for 136A/171Q (AAQQ) and the disease phenotype is similar to that seen with experimental strain CH1641.
***Our transmission study demonstrates that CH 1641-like scrapie is likely to be more virulent than classical scrapie in cattle.
P-088 Transmission of experimental CH1641-like scrapie to bovine PrP overexpression mice
Subject: DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE (similar to exp. BSE in sheep)
Date: Wed, 7 Apr 2004 08:56:36 -0500
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@uni-karlsruhe.de
######## Bovine Spongiform Encephalopathy #########
Date: April 07, 2004 Time: 13:45
DEFRA INVESTIGATES AN UNUSUAL SCRAPIE CASE
The Veterinary Laboratories Agency (VLA) have informed Defra, the Devolved Administrations and the Food Standards Agency of a type of scrapie not previously seen in the UK.
The VLA and other European laboratories with expertise in scrapie-like diseases have now applied several rapid diagnostic methods to tissue samples from a sheep with suspected scrapie. Some of the methods have indicated that the case does not appear to resemble previously recognised cases of scrapie and, although there were differences, it had some characteristics similar to experimental BSE in sheep and also to an experimental strain of sheep scrapie. More importantly, though, microscopic analysis of brain material showed that the case neither resembled previously recognised types of scrapie or experimental BSE in sheep.
A meeting of the scientific experts who performed these analyses, held on the 30th March, concluded that this case could not be considered to be BSE in sheep, although it does not behave like known types of scrapie either. Further investigation will be needed before more can be said about how this unusual result should be described.
Defra's Chief Scientific Adviser, Professor Howard Dalton, said "The UK, and especially the VLA, have played an important part in improving the diagnostic methods available for identifying TSEs in sheep. As we continue to assess more samples with these improved methods it is likely that we will continue to find samples, such as this, which fall outside our current knowledge of the disease. Defra, as it does with all research, will continue to consult scientific experts to ensure that we are investigating these cases using the best available techniques and methods."
The National Scrapie Plan remains unaffected by this new result and SEAC will be consulted in the near future.
Notes to editors
1. Scrapie is a fatal neurological sheep disease belonging to a group of diseases called transmissible spongiform encephalopathies (TSEs), including BSE in cattle and CJD in humans. It has been present in the national flock for over 250 years. It is not considered to be transmissible to humans.
2. There is a theoretical risk that BSE could be present in sheep, masked by scrapie, but it has not been found naturally occurring in sheep.
3. There is as yet no definitive diagnostic method that can rapidly distinguish between different TSEs for example scrapie from BSE. Consequently, from time to time the scrapie surveillance programmes in EU member states throw up unusual results that merit further investigations (Defra press release 371/03 refers http://www.defra.gov.uk/news/2003/030911a.htm)
4. The VLA have applied several different methods to the sample to compare it to a wide range of previously detected scrapie cases, experimental BSE in sheep and an experimental strain of scrapie, termed CH1461. Two main methods have been used in this analysis:-
a. Western blot (WB) This involves taking a sample of the brain and treating it with an enzyme proteinase k to destroy the normal prion protein (PrPC). The diseased form of the protein (PrPSc) is able to withstand this treatment and is then separated from other cellular material on a gel. A blot is taken of the gel and the PrPSc is visualised using specific antibodies.
b. Immunohistochemistry (IHC) This involves taking thin slices of the brain, and by using special (antibody) markers to detect the PrPSc it is possible to see disease specific patterns of PrPSc distribution in the brain under a microscope. The Western blot method found that the sample did not appear to resemble previously recognised cases of scrapie and, although there were some differences, some characteristics were similar to experimental BSE in sheep and also the experimental strain of sheep scrapie, CH1461. IHC found that it neither resembled previously recognised types of scrapie or experimental BSE in sheep
5. The tissue sample has now been analysed using a total of 5 different diagnostic methods claiming to be able to differentiate between scrapie and experimental BSE in sheep. Two were performed at the VLA and three were performed in other European laboratories.
6. The VLA is the European Reference Laboratory for TSEs and is responsible for co-ordinating such investigations into unusual cases. Their findings will be considered by the European Food Safety Authority's committee of TSE experts and in the UK by the Spongiform Encephalopathy Advisory Committee (SEAC).
7. The genotype of the suspect sheep was ARQ/ARQ which is known to be susceptible to some strains of scrapie and, in experiments, to BSE. Background information on scrapie, scrapie genotyping, and the National Scrapie Plan is published on the Defra internet at www.defra.gov.uk/nsp.
8. For information and advice on BSE in sheep from the FSA please consult their web site at www.foodstandards.gov.uk
Public enquiries 08459 335577; Press notices are available on our website www.defra.gov.uk Defra's aim is sustainable development
End
Nobel House 17 Smith Square London SW1P 3JR Website www.defra.gov.uk
http://www.wired-gov.net/
TSS
########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html ############
TSE in Sheep Contingency Planning Assessment of Risk due to BSE Infectivity from Disposal of Sheep A report for DEFRA November 2001
Management Summary It has been recognised for a considerable time that sheep in the United Kingdom may have been infected with BSE. To date no evidence has been found to demonstrate that the national flock is actually infected with the disease. DEFRA have prepared a draft contingency plan in the event that BSE were to be identified in UK sheep. The worst case scenario under this plan is the disposal of the entire UK flock, some 40 million sheep and lambs. This study has estimated the potential exposure of the UK population to BSE infectivity present in sheep in the event that this plan had to be put into effect.
but who would have guessed that such an important experiment/study would have gotton so screwed up, by not being able to tell a sheep brain from a cow brain;
© DEFRA 2002 Item 3- Scrapie Brain pool experiments- Update on current position and audits of samples 3.1 Members were updated on experiments conducted at the Institute of Animal Health (IAH) to examine a pool of scrapie brains collected in the early 1990 s for evidence of BSE. SEAC had previously recommended that the material should be examined by DNA analysis to assess whether the pooled brain material may have been contaminated with bovine tissue. The Laboratory of the Government Chemist (LGC) had been asked to perform the work. Their results were completely unexpected as the analysis detected only bovine material in the sample. SEAC had intended to meet on the 19 October to Agreed version consider the experiment in detail. However, in view of the result, the meeting was cancelled.
Executive Summary An audit of the sample handling procedures at IAH-E was carried out on 24 October 2001 at the request of the Department of the Environment, Food and Rural Affairs (DEFRA), by a team of two UKAS auditors. The scope of the audit was limited to the traceability of cow and sheep brain samples used in several experiments relating to transmissible spongiform encephalopathy (TSE) agents. In particular, the team focused on the audit trail of samples that had been sent to LGC, Teddington, the audit trail of brains collected in 1990/92 by Veterinary Investigation Centres and the audit trail for archived material held by IAH-E. In addition the audit team evaluated the IAH-E procedures against the specific requirements for sampling handling of international standard, ISO 17025 and identified opportunities for improvement. The audit established that there was no formal documented quality system covering this work at IAH-E and that record keeping was inadequate to give confidence in the chain of custody of samples used in the various rendering, genotyping and strain typing experiments audited. It was not possible to establish clear traceability between the samples that had been used in the individual experiments carried out by IAH-E or IAH-C with those analysed at LGC or with those that had been collected in 1990/92. The sample handling procedures covered by this audit at IAH-E did not meet the requirements of ISO 17025.
explaining the brain mixup blunder;
An Investigation of the Substitution of Scrapie Brain Pool Samples A report for DEFRA November 2001
Risk Solutions Page 19 Why did the experimenters not notice that they were working with cow brains not sheep brains? The simple answer is because for the most part they were working with brain pool macerate (minced brain material) not brains. It is not credible that staff collecting brains at VICs would have uniformly supplied cow brains or cow brain parts in mistake for sheep. We have interviewed staff at VICs and we understand from the VLA that records do not support the possibility that significant numbers of cow brains were sent to PDM in place of sheep brains. It is also very unlikely that the people preparing the scrapie brain pool would not have noticed if they were for the most part handling cow brains or cow brain parts in place of sheep brains. We cannot rule out the possibility that some cow brain material entered the brain pool at this stage but it is not feasible that the majority of the material was bovine. The substitution, if substitution occurred, must have involved brain pool macerate or rendered products. Why can t the results of the experiments tell us what material was used? The experiments had a number of features that make the results of the mouse bioassay difficult to interpret unambiguously and lead to the possibility that substitution of the samples would be difficult to detect by examining the results of the experiments: 1. The original experiments were not designed to determine whether BSE was present in sheep. Reasonable efforts were taken to ensure that the brain pool remained free from D5055 02 Issue 1 Risk Solutions Page 20 contamination during preparation but the level of control applied during the earlier experiments (272R and 372R) was not to the standard applied later. 2. Mouse bioassay as a method of diagnosing TSEs is not based on a full understanding of biochemical and physical processes. It is an empirical technique that has been widely applied, for example to show v-CJD is similar to BSE and different from scrapie. It is a complex process and the results need to be interpreted by experts. It can take several years to generate a firm result. The principal data collected in the experiments are lesion profiles (patterns of lesions in the mice brains) and incubation period (time from injection of mice to onset of clinical symptoms. The type of TSE is identified by comparing the results with those of known provenance. There is no good agreed test of sameness of lesion profile , so in marginal cases we are reduced to using subjective observations of the form somewhat similar and interpretation is difficult. The incubation times in principle give a more objective signal, but the effect of concentration has to be controlled. The mouse bioassay data that we understand has been collected and analysed at each stage of the experiments is summarised in Table 4.1. Several features of these experiments are not commonly encountered in mouse bioassay of TSEs and this makes determining the origin of the original material from the experimental results extremely difficult. They include: a. Mouse bioassay is generally carried out on individual brains; experience of working with brain pools is very limited. b. The BBP exhibited a low titre of infectivity, which can confound interpretation of results. c. The BBP comprised bovine brains with the hindbrains removed. By contrast most of the BSE strain typing has been carried out on the hindbrains, which may give a different pattern of results. d. The 272R titrations used a different strain of mice than the 372R titrations, so direct comparison of the resulting lesion profiles cannot be made. e. The 246 experiments used brain pool which was in an unsatisfactorily autolysed state. f. The strain typing data collected (incubation time and lesion profiles) are very sparse. Judging the sameness or difference of samples is a less challenging task for strain typing than identifying a strain and it may be possible to compare data from the 246 experiments with both the 272R and 372R experiments to determine whether the samples are similar or clearly different. However, the data are sparse and the result is unlikely to be clear cut. Much of this work is currently unpublished.
RESPONSE TO THE UKAS REPORT FROM THE INSTITUTE FOR ANIMAL HEALTH
The Institute is concerned, therefore, that the authors of this UKAS report may have based their findings on an unrepresentative and limited examination of procedures in place at IAH-E.
Transmission of prion diseases by blood transfusion
Nora Hunter,1 James Foster,1 Angela Chong,1 Sandra McCutcheon,2 David
Parnham,1 Samantha Eaton,1 Calum MacKenzie1 and Fiona Houston2
TSEs TRANSMISSION STUDIES
what a coincedence , CONVENIENTLY, MORE FLUBBED UP BRAINS;
HOUND STUDY
b) Fibrillar material closely similar to SAF, found in BSE/Scrapie, was observed in 19 (4.3%) cases, all of which were hounds > 7 years of age. 14/19 of these suspected SAF results correlated with cases in the unresolveable histopathological catergory...
HOUND SURVEY (about 72 pages)
Also, at paragraph 17, it is noted that BSE had transmitted to the NPU negative line sheep (please not that as at January 1996, only one of six challenged sheep was clinically affected after oral challenge, four others have since died, and one remains alive. Following intracerebral challenge, three out of six were clinically affected, two confirmed only on pathology, while one was negative.)
4. Meeting 16, on 26/1/94 - the update on research (16/5) confirmed that BSE had been transmitted to sheep, and that there was clinical evidence of transmission to mice from the spleen of the affected sheep.
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IN CONFIDENCE
A STUDY AIMED AT DETERMINING WHETHER OR NOT THERE HAVE BEEN SIGNIFICANT CHANGES IN THE NEUROPATHOLOGY OF SCRAPIE IN SHEEP AND GOATS DURING THE LAST TWO DECADES IN MATERIAL SUBMITTED TO CVL PATHOLOGY DEPARTMENT
EXPERIMENTAL TRANSMISSION OF BSE TO SHEEP
THE RISK OF TRANSMISSION OF BSE TO SHEEP VIA FEED
hell, they knew they were screwing up the sheep brains with cow brains in 1992;
"The sensitivity of the project may be partially compromised by pooling of brains, but it is considered that the success of transmission to mice with BSE will prove advantageous."
'NOT'...tss
Personal $ Confidential -- Addressee only TO ALL MEMBERS OF SEAC
THE EXPERIMENTAL TRANSMISSION OF BSE TO SHEEP
a) Summary of transmission studies. b) Update
The only circumstance in which infection with the natural isolate produces an higher incidence of disease compared to BSE, is in intracerebrally (and possibly orally) challenged ''positive'' line sheep. Notwithstanding the possibility of indigenous natural scrapie in some of these sheep, there are still sufficient numbers of transmission cases with PrP genotypes which preclude the natural disease developing i.e. those typed as VA136/RR154/QR171.
As an extension to this study, it has been possible to recover BSE by passage in mice from brain and spleen taken from ''negative'' line sheep infected with BSAE by ic and oral challenge (Foster and others 1996). The close similarity of incubation periods and pathology from the passage of these tissues in mice to those seen in direct BSE transmission studies from cattle to mice suggests that passaging BSE in sheep does not alter its bilogical properties (Bruce and others 1994). IN FACT, because it has been possible to isolate BSE infectivity from ovine spleens, when this proved impossible from the spleens of naturally infected BSE cows (Fraser and Foster 1993), experimentally-induced BSE in sheep appears to behave more like the natural disease of scrapie.Whether this putative similarity to natural scrapie extends to the possibility of maternal transmission of experimentally-induced BSE in sheep, has till to be elucidated...
we have found a link between BSE and CH1641, a C-group of scrapie. Disease susceptibility of sheep to these isolates is associated with different PrP genotypes compared to SSBP/1 scrapie...
Transmission of BSE in sheep, goats and mice.
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BSE has been transmitted in two lines of genetically selected sheep (differeing in their susceptibilities to the SSBP/1 source of scrapie), and to goats by intracerebral injection AND BY ORAL DOSING.
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Also, intermediate passage of BSE in sheep or goats did not alter these primary transmission properties. Hamsters were susceptible to BSE only after intervening passage through mice...
IN CONFIDENCE
Perceptions of unconventional slow virus in the USA
3. Prof. A Robertson gave a brief account of BSE. The US approach was to accord it a very low profile indeed. Dr. A Thiermann showed the picture in the ''Independent'' with cattle being incinerated and thought this was a fantical incident to be avoided in the USA AT ALL COSTS. BSE was not reported in the USA...........(some good data on CWD)
> avoided in the USA AT ALL COSTS
and indeed they have and it continues today...TSS
BSE TRANSMISSION STUDIES
Furthermore, we showed that the strain responsible for iCJD is closely related to that of one patient with sCJD, and, more unexpectedly, that these agents were similar to the French scrapie strain studied (but different from the U.S. scrapie strain). This finding requires a cautious interpretation for several reasons, not least because of the inevitably limited number of TSE strains that can be studied by such a cumbersome method as strain typing. Nonetheless, it also prompts reconsideration of the possibility that, in some instances, sheep and human TSEs can share a common origin.
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STATEMENT OF DR HELEN GRANT MD FRCP ISSUED 13/05/1999
BSE INQUIRY
Scrapie Singeltary et al
CH1641 TSE PRION
Canine Spongiform Encephalopathy TSE Prion disease and the Hound Study
CWD TO PIGS
Research Project: TRANSMISSION, DIFFERENTIATION, AND PATHOBIOLOGY OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES
Location: Virus and Prion Research
Title: Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease
Author item Moore, Sarah item Kunkle, Robert item Kondru, Naveen item Manne, Sireesha item Smith, Jodi item Kanthasamy, Anumantha item West Greenlee, M item Greenlee, Justin
Submitted to: Prion Publication Type: Abstract Only Publication Acceptance Date: 3/15/2017 Publication Date: N/A Citation: N/A Interpretive Summary:
Technical Abstract: Aims: Chronic wasting disease (CWD) is a naturally-occurring, fatal neurodegenerative disease of cervids. We previously demonstrated that disease-associated prion protein (PrPSc) can be detected in the brain and retina from pigs challenged intracranially or orally with the CWD agent. In that study, neurological signs consistent with prion disease were observed only in one pig: an intracranially challenged pig that was euthanized at 64 months post-challenge. The purpose of this study was to use an antigen-capture immunoassay (EIA) and real-time quaking-induced conversion (QuIC) to determine whether PrPSc is present in lymphoid tissues from pigs challenged with the CWD agent.
Methods: At two months of age, crossbred pigs were challenged by the intracranial route (n=20), oral route (n=19), or were left unchallenged (n=9). At approximately 6 months of age, the time at which commercial pigs reach market weight, half of the pigs in each group were culled (<6 challenge="" groups="" month="" pigs="" remaining="" the="">6 month challenge groups) were allowed to incubate for up to 73 months post challenge (mpc). The retropharyngeal lymph node (RPLN) was screened for the presence of PrPSc by EIA and immunohistochemistry (IHC). The RPLN, palatine tonsil, and mesenteric lymph node (MLN) from 6-7 pigs per challenge group were also tested using EIA and QuIC.
Results: PrPSc was not detected by EIA and IHC in any RPLNs. All tonsils and MLNs were negative by IHC, though the MLN from one pig in the oral <6 5="" 6="" at="" by="" detected="" eia.="" examined="" group="" in="" intracranial="" least="" lymphoid="" month="" months="" of="" one="" pigs="" positive="" prpsc="" quic="" the="" tissues="" was="">6 months group, 5/6 pigs in the oral <6 4="" and="" group="" months="" oral="">6 months group. Overall, the MLN was positive in 14/19 (74%) of samples examined, the RPLN in 8/18 (44%), and the tonsil in 10/25 (40%). Conclusions:
This study demonstrates that PrPSc accumulates in lymphoid tissues from pigs challenged intracranially or orally with the CWD agent, and can be detected as early as 4 months after challenge.
CWD-infected pigs rarely develop clinical disease and if they do, they do so after a long incubation period. This raises the possibility that CWD-infected pigs could shed prions into their environment long before they develop clinical disease.
Furthermore, lymphoid tissues from CWD-infected pigs could present a potential source of CWD infectivity in the animal and human food chains.
CONFIDENTIAL
EXPERIMENTAL PORCINE SPONGIFORM ENCEPHALOPATHY
While this clearly is a cause for concern we should not jump to the conclusion that this means that pigs will necessarily be infected by bone and meat meal fed by the oral route as is the case with cattle. ...
we cannot rule out the possibility that unrecognised subclinical spongiform encephalopathy could be present in British pigs though there is no evidence for this: only with parenteral/implantable pharmaceuticals/devices is the theoretical risk to humans of sufficient concern to consider any action.
Our records show that while some use is made of porcine materials in medicinal products, the only products which would appear to be in a hypothetically ''higher risk'' area are the adrenocorticotrophic hormone for which the source material comes from outside the United Kingdom, namely America China Sweden France and Germany. The products are manufactured by Ferring and Armour. A further product, ''Zenoderm Corium implant'' manufactured by Ethicon, makes use of porcine skin - which is not considered to be a ''high risk'' tissue, but one of its uses is described in the data sheet as ''in dural replacement''. This product is sourced from the United Kingdom.....
snip...see much more here ;
WEDNESDAY, APRIL 05, 2017
Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease
WEDNESDAY, APRIL 05, 2017
*** Disease-associated prion protein detected in lymphoid tissues from pigs challenged with the agent of chronic wasting disease ***
cattle are highly susceptible to white-tailed deer CWD and mule deer CWD
***In contrast, cattle are highly susceptible to white-tailed deer CWD and mule deer CWD in experimental conditions but no natural CWD infections in cattle have been reported (Sigurdson, 2008; Hamir et al., 2006). It is not known how susceptible humans are to CWD but given that the prion can be present in muscle, it is likely that humans have been exposed to the agent via consumption of venison (Sigurdson, 2008). Initial experimental research, however, suggests that human susceptibility to CWD is low and there may be a robust species barrier for CWD transmission to humans (Sigurdson, 2008). It is apparent, though, that CWD is affecting wild and farmed cervid populations in endemic areas with some deer populations decreasing as a result.
SNIP...
price of prion poker goes up for cwd to cattle;
Monday, April 04, 2016
*** Limited amplification of chronic wasting disease prions in the peripheral tissues of intracerebrally inoculated cattle ***
*** The potential impact of prion diseases on human health was greatly magnified by the recognition that interspecies transfer of BSE to humans by beef ingestion resulted in vCJD. While changes in animal feed constituents and slaughter practices appear to have curtailed vCJD, there is concern that CWD of free-ranging deer and elk in the U.S. might also cross the species barrier. Thus, consuming venison could be a source of human prion disease. Whether BSE and CWD represent interspecies scrapie transfer or are newly arisen prion diseases is unknown. Therefore, the possibility of transmission of prion disease through other food animals cannot be ruled out. There is evidence that vCJD can be transmitted through blood transfusion. There is likely a pool of unknown size of asymptomatic individuals infected with vCJD, and there may be asymptomatic individuals infected with the CWD equivalent. These circumstances represent a potential threat to blood, blood products, and plasma supplies.
Friday, December 14, 2012
DEFRA U.K. What is the risk of Chronic Wasting Disease CWD being introduced into Great Britain? A Qualitative Risk Assessment October 2012
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In the USA, under the Food and Drug Administration's BSE Feed Regulation (21 CFR 589.2000) most material (exceptions include milk, tallow, and gelatin) from deer and elk is prohibited for use in feed for ruminant animals. With regards to feed for non-ruminant animals, under FDA law, CWD positive deer may not be used for any animal feed or feed ingredients. For elk and deer considered at high risk for CWD, the FDA recommends that these animals do not enter the animal feed system. However, this recommendation is guidance and not a requirement by law.
Animals considered at high risk for CWD include:
1) animals from areas declared to be endemic for CWD and/or to be CWD eradication zones and
2) deer and elk that at some time during the 60-month period prior to slaughter were in a captive herd that contained a CWD-positive animal.
Therefore, in the USA, materials from cervids other than CWD positive animals may be used in animal feed and feed ingredients for non-ruminants.
The amount of animal PAP that is of deer and/or elk origin imported from the USA to GB can not be determined, however, as it is not specified in TRACES. It may constitute a small percentage of the 8412 kilos of non-fish origin processed animal proteins that were imported from US into GB in 2011.
Overall, therefore, it is considered there is a __greater than negligible risk___ that (nonruminant) animal feed and pet food containing deer and/or elk protein is imported into GB.
There is uncertainty associated with this estimate given the lack of data on the amount of deer and/or elk protein possibly being imported in these products.
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36% in 2007 (Almberg et al., 2011). In such areas, population declines of deer of up to 30 to 50% have been observed (Almberg et al., 2011). In areas of Colorado, the prevalence can be as high as 30% (EFSA, 2011).
The clinical signs of CWD in affected adults are weight loss and behavioural changes that can span weeks or months (Williams, 2005). In addition, signs might include excessive salivation, behavioural alterations including a fixed stare and changes in interaction with other animals in the herd, and an altered stance (Williams, 2005). These signs are indistinguishable from cervids experimentally infected with bovine spongiform encephalopathy (BSE).
Given this, if CWD was to be introduced into countries with BSE such as GB, for example, infected deer populations would need to be tested to differentiate if they were infected with CWD or BSE to minimise the risk of BSE entering the human food-chain via affected venison.
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The rate of transmission of CWD has been reported to be as high as 30% and can approach 100% among captive animals in endemic areas (Safar et al., 2008).
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In summary, in endemic areas, there is a medium probability that the soil and surrounding environment is contaminated with CWD prions and in a bioavailable form. In rural areas where CWD has not been reported and deer are present, there is a greater than negligible risk the soil is contaminated with CWD prion.
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In summary, given the volume of tourists, hunters and servicemen moving between GB and North America, the probability of at least one person travelling to/from a CWD affected area and, in doing so, contaminating their clothing, footwear and/or equipment prior to arriving in GB is greater than negligible. For deer hunters, specifically, the risk is likely to be greater given the increased contact with deer and their environment. However, there is significant uncertainty associated with these estimates.
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Therefore, it is considered that farmed and park deer may have a higher probability of exposure to CWD transferred to the environment than wild deer given the restricted habitat range and higher frequency of contact with tourists and returning GB residents.
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SATURDAY, FEBRUARY 10, 2018
SEE 2017 HUNT CWD FIGURES COMING IN STATE BY STATE...terry
Chronic wasting disease management in ranched elk using rectal biopsy testing Research Paper 09 Feb 2018
i am thinking of that 10,000,000 POUNDS OF BLOOD LACED MEAT AND BONE MEAL IN COMMERCE WARNING LETTER back in 2007, see;
SATURDAY, NOVEMBER 4, 2017
FDA 589.2000, Section 21 C.F.R. Animal Proteins Prohibited in Ruminant Feed WARNING Letters and FEED MILL VIOLATIONS OBSERVATIONS 2017 to 2006
FRIDAY, NOVEMBER 3, 2017
BSE MAD COW TSE PRION DISEASE PET FOOD FEED IN COMMERCE INDUSTRY VS TERRY S. SINGELTARY Sr. A REVIEW
''I have a neighbor who is a dairy farmer. He tells me that he knows of several farmers who feed their cattle expired dog food. These farmers are unaware of any dangers posed to their cattle from the pet food contents. For these farmers, the pet food is just another source of protein.''
IN CONFIDENCE
Terry S. Singeltary Sr.
posted by Terry S. Singeltary Sr. | 2:00 PM
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